Transverse flow blower for discharging fluid in a path defined by a surface



May 27, 1969 Filed April 5, 1967 R. w. BORNSTEIN 3,446,426: TRANSVERSE FLOW BLOWER FOR DISCHARGING FLUID IN A PATH DEFINED BY A SURFACE Sheet of 2 May 27, 9 R. w. BORNSTEIN 3, 4

TRANSVERSE FLOW BLOWER FOR DISCHARGING r FLUID IN A PATH DEFINED BY A SURFACE Filed April 3, 19 7 Sheet 2 '01 2 US. Cl. 230-125 10 Claims ABSTRACT OF THE DISCLOSURE A transverse flow blower for receiving fluid on one side of a dividing wall or the like and discharging a wide stream or curtain of fluid at relatively low velocity on the opposite side thereof and in a path of flow generally defined by the wall surface. The blower has a housing including a fluid flow discharge passageway terminating in a fluid outlet opening associated with the wall and constructed and arranged to minimize loss of angular momentum imparted to a fluid flow stream by a rotor so that the flow stream gradually dissipates as it flows along the wall.

Cross reference to related application Background of invention This invention relates in general to transverse flow blowers and deals more particularly with a blower of the type used in ventilating, heating, air conditioning and defrosting systems to discharge a curtain of fluid or air along a path generally defined by a surface. While the blower of the present invention is suitable for a wide variety of fluid conveying application, such as may be encountered in the aforementioned systems, it is particularly adapted for ventilating a cabinet housing electronic equipment or the like by exhausting the cabinet to induce a forced draft therethrough. A blower suitable for such purpose must be capable of efficiently ventilating electrical components which are widely spaced apart within a cabinet. It is further desirable that such a blower be relatively inaudible in operation and discharge air so as to avoid creation of objectionable drafts which tend to agitate curtains, drapes and other room accessories. While it is not feasible to wholly eliminate the resulting draft condition where air is exhausted from a cabinet and into room atmosphere, the latter condition may be satisfactorily controlled by employing a blower arranged to discharge air in a relatively wide stream along a surface of the cabinet and at a velocity sufficient to cause gradual dissipation of the stream to occur at points somewhat remote from the blower discharge outlet. Accordingly the general aim of this invention is to provide a blower receiving a relatively wide fluid stream and operable at low noise level to discharge fluid at low velocity and along a predetermined path generally defined by a surface.

Summary of invention In accordance with the present invention, a transverse flow blower is provided having a housing containing a rotor for imparting angular momentum to a fluid stream and including walls defining a generally curved fluid discharge passageway terminating in a fluid outlet opening. The blower is arranged with respect to a dividing wall to discharge fluid transversely of the surface thereof and at 3,446,426 Patented May 27, l$69 an acute angle thereto so that fluid so discharged tends to assume a flow path generally defined by the latter surface and flow therealong due to so-called Coanda effect. The construction and arrangement of the housing walls is such that angular momentum imparted to a fluid stream by the rotor is substantially retained by the fluid stream as it passes through the discharge passageway and the outlet opening thereby reinforcing the Coanda effect or effecting a more eflicient flow of fluid along the surface of the dividing wall so that no appreciable diffusion of the fluid stream occurs in the immediate vicinity of the discharge opening.

Brief description of drawings FIG. 1 is an end view of a transverse flow blower embodying the present invention, and shows the blower mounted in an operational position on a cabinet dividing wall, a portion of the wall being shown in section.

FIG. 2 is a fragmentary side elevational view of the blower of FIG. 1, portions of the blower housing being shown broken away to reveal structure therein.

FIG. 3 is a somewhat enlarged transverse sectional view through the blower and cabinet wall of FIG. 1 taken along the line 33 of FIG. 2.

FIG. 4 is a fragmentary view of the blower of FIG. 1 as viewed from below or looking toward the discharge outlet.

Detailed description of the preferred embodiment In the drawings, a transverse flow blower embodying the present invention and indicated generally at 10 is shown mounted in an operational position relative to a dividing wall 12, which may, for example, represent the rear wall of a cabinet 14 housing a television receiver (not shown). Formed in the wall 12 is a horizontally extending slot 16 through which fluid discharged from the blower is constrained to flow. The blower 10 has a housing 18 including a fluid inlet 20, a pressure chamber 22, and a discharge passageway 24 communicating with the pressure chamber and a fluid outlet opening 26. Fluid conveyed by an axially elongated rotor 28 flows from the inlet opening 20 to the passageway 24 and the outlet opening 26 generally along a path indicated by the arrows in FIG. 3. A portion of the fluid that flows from the inlet and through the rotor is directly discharged through the outlet, however, a portion of the fluid also rotates about a vortex center such as indicated at 30 in the same direction as the rotor and reenters and recirculates therethrough. The operational characteristics of the blower are such that a relatively light duty two-pole electrical motor 32 provides suflicient power to operate it effectively.

The rotor may be made in various forms and may, for example, comprise one or more rotor units joined together in coaxial alignment and in end-to-end relationship. In the illustrated case the rotor 28 is generally drumshaped and includes a circumaxially spaced series of axially elongated blades 34, 34 mounted between an axially spaced pair of support members 36, 36 which may, for example, be rings or discs.

Preferably, the rotor is journaled for rotation in the inlet opening 20 with not more than a 200 arc of the periphery thereof disposed in the chamber 22. At one of its ends the rotor is drivingly supported by a shaft 38 on the motor 32 for rotation in a clockwise direction as shown in FIG. 3. The support member 36 at the other end of the rotor carries a coaxially projecting shaft portion 40 which is journaled in the housing.

The housing may be made from various materials and in various forms but preferably it is molded in two sections from a plastic material and joined together in assembly in a manner described. in the aforementioned c0- pending application to Kenny et al. The housing 18 generally comprises two axially spaced end walls 42 and 44 connected together by spaced apart generally axially extending inner and outer walls respectively indicated at 46 and 48 and hereinafter further described. To provide a means for mounting the blower on the wall 12, a lug 50 projects outwardly from each of the end walls 42 and 44. Each lug has a downwardly opening generally U-shaped recess 52 which straddles an associated portion of the wall 12 at the lower edge of the slot 16. Each of the end walls 42 and 44 further includes a rearwardly projecting upper portion 54 terminating at a mounting flange 56 which abuts the wall 12 and is secured thereto by a fastener 58. The end wall 42 is apertured to receive the motor shaft 38 and has two motor mounting bosses 60, 60 projecting outwardly, therefrom and threadably receiving fasteners 62, 62 securing the motor 32 in an operational position on the housing. The opposite end wall 44 has an axially outwardly projecting central portion 64 defining an inwardly opening recess receiving and retaining a cartridge bearing 66 in which the shaft portion 40 is journaled. For a further description of the manner in which the latter bearing is or may be retained in the housing further reference may be had to the aforementioned patent to Kenny et al.

Considering the housing in further detail and now referring particularly to FIG. 3, the outer wall 48 includes a generally particylindrical first part 68 concave inwardly and partially defining the pressure chamber 22 and preferably having its center of curvature proximate the vortex center. An axially extending forward edge 70 of the first part is radially spaced from the rotor 28 and partially defines the rectangular inlet opening 20. The first part 68 curves gradually outwardly from the rotor and in the direction of rotation through an arc of approximately 165 degrees and proximate the outlet opening 26 is radially spaced a substantial distance from the rotor periphery to provide space for the generation of a vortex such as indicated at 30. A contiguous second part 72 is convex inwardly and joins the first part and provides a reverse curve section to partially define the discharge passageway 24. The outer wall 48 may terminate at the wall 12 but preferably and as shown it further includes a third continguous part 74 concave inwardly and joining the second part proximate the wall 12, The hood-like extension formed by the third part curves outwardly from the second part and in the direction of rotor rotation rearwardly of the dividing wall 12. The third part prevents the cabinet 14 from being positioned with its dividing wall 12 immediately adjacent another wall or object which might block the flow of fluid from the outlet opening 26. It further serves as a guard to prevent accidental contact with the rotor 28.

The passageway 24 is further defined by the inner wall 46 which may comprise a mere cutoff point as may be provided by the dividing wall 12. Preferably the inner wall extends from an axially extending inner or cutoff edge 78 proximate the periphery of the rotor 28 to an axially extending outer edge arranged at the outlet opening 26. Most of the noise in the blower originates at the cutoff edge. The effect upon blower efficiency of a reasonably large clearance between cutoff edge and the rotor is negligible, consequently the cutoff edge 78 may be positioned adjacent the rotor or may be spaced radially outwardly therefrom a distance not exceeding the radius dimension of the rotor. In the presently preferred embodiment operational noise is attenuated without appreciable loss of efficiency by providing spacing between the rotor and the cutoff edge equal to approximately 20 percent of the rotor diameter.

The inner wall 46 is convex inwardly and curves gradually outwardly from the rotor and in the direction of rotor rotation and has a radius of curvature 80 greater than 0.6 but less than 3 times the rotor diameter. Preferably the radius of curvature 80 is equal to approximately twice the rotor diameter. At its ou er en h i r W ll 4 terminates in an axially extending edge 82 adjacent the lower edge of the slot 16 which further defines the outlet opening 26. The inner wall 46 and the outer wall 48 as viewed throughout their length as in FIG. 3 generally converge from the inlet opening 20 to the outlet opening 26. The blower 10 is supported relative to the wall 12 so that a median plane of the passageway 24 parallel to the rotor axis and indicated at 84 intersects the plane of the dividing wall at an acute angle 86. Preferably, the angle 86 is less than 60.

Finally, there is positioned within the passageway 24, a plurality of axially spaced turning vanes 88, 88. Each vane 88 extends between the passageway walls 46 and 48 and has an outer edge 90 generally disposed in the plane of the outlet 26. Each vane is inclined outwardly relative to the center of the passageway and in the direction of air flow to spread or turn the emerging stream of air outwardly toward an axial direction.

The aerodynamic characteristics of a transverse flow blower are such that the path of the flow stream both inside and outside of the rotor is that of a potential vortex that is, each fluid particle in the flow stream tends to travel in a path concentric with the vortex center 30, the center of the particle path being located somewhere in the interior of the rotor. In the blower of the present invention the construction and arrangement of the housing walls 46 and 48 complement this aerodynamic characteristic. Thus the outer wall first part 68 which preferably has its center of curvature proximate the vortex center 30 serves to reinforce the natural tendency of the fluid particles to flow in an arcuate path. The inner Wall 46 serves to further complement this natural flow tendency and has its outer edge 82 arranged almost tangent to the desired flow direction but spaced from the rotor periphery a distance insufficient to effect a substantial straightening effect on the flow stream as night tend to overcome the angular momentum of the stream. In order to prevent separation of the flow stream from the edge 82 the stream is forced to accelerate as it approaches the outer wall second part 72. The emerging flow stream once started in the direction of the dividing wall surface will adhere to the latter surface owing to Coanda effect.

I claim:

1. The combination of a transverse flow blower assembly and a slotted dividing wall, said blower assembly receiving fluid on one side of the dividing wall and discharging fluid through a slot therein on the other side thereof and in a path of flow adjacent the surface thereof, said assembly comprising a rotor on said one side of said wall on an axis parallel with the major dimension of the wall discharge slot and including a circumaxially spaced series of axially elongated and radially outwardly spaced blades, a generally U-shaped housing on said one side of said wall having spaced apart generally axially extending inner and outer walls defined a fluid inlet opening, a pressure chamber, and a fluid outlet opening at said wall discharge slot, said rotor being at least partially disposed in said chamber and rotatable in a predetermined direction to convey fluid from said inlet opening to said outlet opening, said outer housing wall being concave viewed interiorly and having a gradual arcuate configuration throughout and including a part radially spaced a substantial distance from said rotor periphery adjacent said outlet opening to provide space for the generation of a vortex on said one side of said wall, said wall part following a curve at least approximately coincident with fluid flow at an outer portion of the vortex and said outer housing wall forming an acute angle with the plane of said dividing wall at said outlet opening whereby to tend to maintain the angular momentum of the fluid stream emitted from the outlet opening for the flow of said fluid stream along said wall surface, said inner housing wall serving to provide a cutoff point spaced from the rotor periphery and having an axially extending outer edge arranged at said outlet opening and spaced from said rotor periphery a distance insuflicient to effect substantial straightening effect on sad fluid stream as might tend to overcome said angular momentum, and said outer and inner housing walls defining a discharge passageway adjacent said outlet opening and having a median plane parallel to the rotor axis and which intersects the plane of said dividing wall at an acute angle less than 60 in the direction of air flow whereby discharge air clings to and fiows along said other side of said wall due to the angular momentum of the air leaving said vortex.

2. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said inner and outer walls converge toward said outlet opening to provide a discharge passageway which preserves energy and prevents loss of angular momentum in the air stream.

3. The combination in a transverse flow blower assembly as set forth in claim 2 wherein said inner wall is of substantial length extending from an inner axially extending edge spaced from the rotor periphery and providing said cutoff point to said outer edge, and wherein said outer wall includes a short reversely curved part generally adjacent said outlet opening.

4. The combination in a transverse flow blower assembly as set forth in claim 1 wherein not more than a 200 arc of the periphery of said rotor is disposed within said chamber.

5. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said inner wall has a radius of curvature greater than .6 times the diameter of said rotor and less than 3 times diameter.

6. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said inner wall has a radius of curvature approximately equal to the diameter of said rotor.

7. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said inner wall inner edge is spaced generally radially outwardly from r e periphery of said rotor a distance not greater than the radius of said rotor. 1

8. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said housing includes a plurality of axially spaced turning vanes positioned proximate said outet opening for directing fluid flow angularly outwardly toward an axial direction therefrom. t

9. The combination in a transverse fiow blower assembly as set forth in claim 1 wherein said inner wall inner edge is spaced from the periphery of said rotor a distance approximately equal to 20 percent (20%) of the diameter of said rotor.

10. The combination in a transverse flow blower assembly as set forth in claim 1 wherein said outer wall part has a center of curvature proximate the center of the vortex.

References Cited UNITED STATES PATENTS 3,178,100 4/ 1965 Datwyler.

3,275,224 9/ 1966 Bush.

3,295,750 1/ 1967 Laing.

3,319,877 5/1967 Eck et al.

3,362,469 1/ 1968 Berner et al.

FOREIGN PATENTS 955,967 4/ 1964 Great Britain.

1,015,486 12/1965 Great Britain.

HENRY F. RADUAZO, Primary Examiner.

US. Cl. X.R. 9839; 230133, 235 

